(1) Field of the Invention
This invention relates to a process for preparing cinnamate esters by the reaction of styrene compounds, carbon monoxide, alcohols and oxygen.
(2) Description of the Prior Art
Cinnamate esters have found wide-spread commercial utility as perfumes and raw materials therefor owing to their inherent aroma. They are also important as raw materials for agricultural chemicals and photosensitive resins.
Cinnamic acid has conventionally been produced on small scales by using benzaldehyde and derivatives of acetic acid as principal raw materials. This process is however not preferred from the industrial viewpoint since it requires such costly raw materials. As processes permitting use of more economical raw materials, several processes have been proposed to prepare a cinnamate ester by reacting a styrene compound, carbon monoxide, an alcohol and oxygen in the presence of a catalyst (see, for example, Japanese Patent Laid-Open No. 15242/1981, etc.).
In these processes, however, the activities of catalysts are still low and therefore expensive metals have to be used in large amounts as the catalysts. For these reasons, they have not yet been practiced on any industrial scales.